“B型不能是C的超接口;超级接口必须是一个接口“错误 [英] "The type B cannot be a superinterface of C; a superinterface must be an interface" error

问题描述

我们假设我有这个界面A：

Let's assume I got this interface A:

interface A
{
    void doThis();
    String doThat();
}

所以，我想要一些摘要类来实现方法doThis（）但不是doThat（）一：

So, I want some abstracts classes to implement the method doThis() but not the doThat() one:

abstract class B implements A
{
    public void doThis()
    {
        System.out.println("do this and then "+ doThat());
    }

}

abstract class B2 implements A
{
    public void doThis()
    {
        System.out.println(doThat() + "and then do this");
    }
}

当你最终决定实施de doThat时出现错误常规类中的方法：

There error comes when you finally decide to implement de doThat method in a regular class:

public class C implements B
{
    public String doThat()
    {
        return "do that";
    }
}

这个课程让我看到上述错误：

This class leads me to the error aforementioned:

类型B不能是C的超接口;超级接口必须是接口

"The type B cannot be a superinterface of C; a superinterface must be an interface"

如果这个类的层次结构有效或者我应该采取其他方式吗？

Anyone could now if this hierarchy of classes is valid or should I do other way round?

推荐答案

您必须使用 extends

public class C extends B

了解工具和扩展关键字。所以，我建议你开始阅读这个问题： Implements vs extends ：什么时候使用？有什么区别？和那里的答案。

Its important to understand the difference between the implements and extends Keywords. So, I recommend you start reading at this question: Implements vs extends: When to use? What's the difference? and the answers there.

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